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Precast lightweight concrete wall panels from plastic waste and household ash as partially sand and cement replacement

Sastrawidana I.D.K., Sukarta I. N.

Archives of Materials Science and Engineering

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2024

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Vol. 125, nr 1

22--31

EN

Purpose: The present study aims to investigate the properties of precast lightweight concrete wall panels prepared with the addition of plastic powder and household ash as a partial substitution for sand and cement. Design/methodology/approach: Eight formulations of lightweight concrete wall panels were prepared using a mix. The proportion of sand-to-cement ratio of 3:1 by weight and water-to-cement ratio of 1.85. Subsequently, sand and cement were gradually replaced with plastic powder and household ash. Plastic has water-repellent properties, while household ash is a natural pozzolan with cementitious properties in the presence of water and calcium hydroxide. Therefore, adding both materials in certain proportions should improve the quality of concrete wall panels. The mixture was cast in a fibreglass mould with length, width, and thickness dimensions of 30 x 30 x 3 cm. The evaluations of precast lightweight concrete wall panels include density tests, water absorption, compressive strength, water absorption-desorption capacity, and surface morphology. Findings: Replacing 20% of sand and 10% of cement with plastic powder and household ash produces lightweight concrete wall panels with a density, water absorption, and compressive strength of 1512.2 kg/m3, 7.95%, and 3.78 MPa, respectively. These precast concrete wall panels are acceptable for lightweight concrete wall panel requirements according to ASTM C129-06. Research limitations/implications: In this research, lightweight concrete wall panels were prepared by adding PET plastic powder and household ash to replace the sand and cement partially. In further research, it is necessary to assess the precast lightweight wall panels prepared from other plastic types and natural pozzolans. Practical implications: Using plastic waste reinforced with household ash as a partial substitute for sand and cement can create eco-friendly precast lightweight concrete wall panels. This is an effort to reduce sand and cement usage in concrete wall panel production and as an innovative way to reduce plastic waste in the environment. Originality/value: It has been experimentally proven that utilising plastic powder of up to 20% and household ash of up to 10% by weight for partial replacement sand and cement in preparation of precast lightweight concrete wall panels fully meets standard materials for manufacturing according to ASTM C129-06 standard for non-loading-bearing lightweight concrete. The addition of plastic makes the colour of the concrete wall panels' surface more attractive.

2

Plastic waste reinforced with inorganic pigment from red stone in manufacturing paving block for pedestrian application

Sastrawidana D. K., Sukarta I. N., Saraswati L. P. A., Maryam S., Putra G. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2022

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Vol. 110, nr 2

49--58

EN

Purpose: This study was aimed to investigate the effectiveness of plastic waste as fine aggregates to partial replacement of sand reinforced with inorganic pigment from red stone to manufacture paving block for pedestrian application. This is an effort not only to reduce plastic waste in the environment but also as an innovative way to find out an alternative eco-friendly paving block material for public walkways with an attractive appearance while ensuring pedestrian comfort. Design/methodology/approach: Approaches were converted the plastic waste to plastic powder which is then used as fine particles to sand partial replacement. The red stone powder is used to give red color to the paving block surface. The paving block materials were completely mixed in a pan mixer and added water as much as 12% of the total mass of the materials used. The paving block was cast in a mold dimension size of 20 cm × 10 cm × 6 cm and pressed with a load of 6 tons using a pressing machine. The effect of natural river sand to plastic powder ratio and curing time on the compressive strength and water absorption were investigated. Findings: The study results confirmed that the replacement of sand with plastic powder decreased the compressive strength of paving block. By partial replacement of sand with plastic powder in the range of 10% to 50% by weight, the compressive strength and water absorption value of pavement after 30 days agitation were at range of 18.06-12.78 MPa and 4.28-3.25%, respectively. This value was still met the minimum requirement for pedestrian applications according to Indonesian National Standard. Research limitations/implications: Replacing sand up to 50% by weight with plastic waste produces paving blocks with compressive strength and water absorption suitable for sidewalks and pedestrians. It is needed to continue research in terms of durability tests in order to be comfortable with the practical use of the material. Practical implications: The use of plastic waste reinforced with red stone powder as fine aggregate makes it one of the alternative ways to reduce plastic waste in the environment and obtain eco-friendly paving blocks with an attractive appearance. Originality/value: It has been experimentally proven that replacing sand up to 50% by weight with plastic powder produces paving blocks that are suitable for pedestrians application. The addition of red stone powder pigment makes the color of paving block surface become more attractive appearance.

3

Proximate Analysis and Calorific Value of Pellets in Biosolid Combined with Wood Waste Biomass

Sukarta I. N., Sastrawidana I. D. K., Ayuni N. P. S.

Journal of Ecological Engineering

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2018

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Vol. 19, nr 3

185--190

EN

In this study, biosolid and wood waste biomass were used as fuel by turning them into fuel pellets. The purpose of making fuel pellets with various compositions was to compare the type of biosolid pellets and wood waste in terms of proximate testing. The benefits of making biosolid pellets can reduce the landfill waste that contributes to the environmental pollution. The results of this research showed the highest water content that is equal to 10.07% was found in the wood waste pellets with the composition of (90:10; the highest ash content, amounting to 33.19% was found in the pellets with the composition of (50:50); the highest value of volatile substances (74.05%) was contained in pellets with the composition (90:10); the highest value of solid carbon (10.13%) was found in the pellets with the composition of (80:20) Meanwhile, the highest calorific value was exhibited by the pellets with the composition of wood waste and biosolid (90:10), equalling 3.822 cal/g.

4

Indirect Electrochemical Oxidation with Multi Carbon Electrodes for Restaurant Wastewater Treatment

Sastrawidana I. D. K., Sukarta I. N.

Journal of Ecological Engineering

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2018

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Vol. 19, nr 1

200--204

EN

The removal of organic matter from the restaurant wastewater was investigated using the electrochemical oxidation method with multi carbon electrodes in a parallel construction. The degradation process was monitored by the measurement of COD concentration as a function of electrolysis time. The effect of operating parameter conditions on COD removal were investigated including initial pH, distance between electrodes, and the applied voltage difference. The results showed that the treatment of restaurant wastewater containing 2 g/L chloride ion using the electrochemical oxidation technique at the operation conditions characterized by: pH 5, distance between electrode of 10 cm and applied voltage of 12 V, enabled to obtained COD removal of 92.84% within 90 min electrolysis time. It is can be concluded that the indirect electrochemical oxidation method with multi carbon electrodes can be used effectively as an alternative technology for reducing COD and may be potentially applied for removal organic pollutants from wastewater at the industrial scale.